Boots of this kind are designed for sports requiring effective transmission to the foot of the forces generated by the user's leg, in order to obtain better traction, gripping of the ski edge, or enhanced momentum.
These sports include sliding sports such as skiing, cross-country skiing, snowboarding, skateboarding, in-line skating, etc., but also walking sports requiring that the foot be extended or the ankle bent in relation to the foot, for example, snowshoeing, cross-country skiing, walking, hiking, etc.
In all of these cases, the forces generated by the user's leg are transmitted through the ankle to the foot. Accordingly, the ankle must be held laterally in position sufficiently to ensure the continuous transmission of information and stresses from the leg to the foot.
To meet this requirement, the boots designed for the practice of these sports are normally fitted with lateral reinforcing pieces in the upper portion surrounding the ankle.
Depending on the sport, moreover, these lateral reinforcing pieces are designed to permit or prevent movements of ankle flexion in relation to the foot, these movements occurring basically in the longitudinal direction of the foot.
Thus, FR 2 651 416 suggests fitting the upper of a sport boot with a rigid collar hinged on this upper. This collar provides excellent lateral position maintenance of the ankle, while ensuring excellent front-to-back mobility of the ankle in relation to the foot. A structure of this kind is, accordingly, particularly well suited to the practice of sports requiring front-to-back mobility of the ankle in relation to the foot, that is, walking, cross-country skiing, skating, etc.
In sports where this front-to-back mobility of the ankle in relation to the foot is not desired, the boot is generally manufactured as a shell made of a rigid material, normally a plastic, surmounted by a collar, a cuff, etc. made of one or several components and rigidly enclosing the ankle and/or lower leg of the user and being allowed only very restricted motion, or even no motion at all, in relation to the shell. These boots typically include alpine ski boots and some skating boots. Conventional practice also include reinforcing the portion enclosing the ankle of a boot only with reinforcing pieces arranged laterally and medially, that is, extending toward the outside and inside of the foot.